1. Field of the Invention
The present invention relates to a video printer for making a hard copy from a video signal input from a video tape recorder (VTR) or the like. The present invention relates more particularly to a video printer which facilitates deleting an image displayed on a monitor in an entire area or in a section of a frame by muting the video data with predetermined mute data.
2. Related Art
As is known in the art, a video printer converts an analog video signal such as that from a VTR or an electric still camera, into digital data, and writes the digital data in an image memory such as a frame memory or a field memory, while processing the digital data so as to make an appropriate hard copy of an image based upon the digital data.
It is also known that the video printer can make a multi-frame print other than an ordinary single-frame print having a frame of image printed in the entire area of a sheet of recording medium. In the multi-frame print, four, nine or sixteen frames of images are printed in a matrix on a recording sheet at a reduction rate of 1/2, 1/3 or 1/4, relative to the ordinary size frame. There are also two types of multi-frame print: one is a print having a matrix of different images, the other is a print having a matrix of identical images. In and the video printer, a memory key or freeze key is operated to memorize or freeze data of an image to be printed while monitoring the image on a video display device. For example, for the multi-frame print, the memory key is operated a number of times corresponding to the number of frames to be included in a multi-frame print. Each time the memory key is operated, a frame of an image is written in a designated location of the image memory after being reduced in size at a rate corresponding to the divisional number, that is, the number of sub-frames into which the ordinary size frame should be divided for the multi-frame print. After checking the arrangement and the content of the sub-frames on the monitor, a print key is operated to execute printing.
However, in the above-described printer, it is necessary to revise a memorized image to rewrite the image memory with another image. Therefore, in order to keep a sub-frame of a multi-frame print blank, it has been necessary to pick up a white plane image by a camera and write the white plane image in a memory location corresponding to that sub-frame.
If the memory key is operated while no video signal is input to the video printer, a noise image would be memorized and displayed on the monitor. The conventional solution for the problem is to disable the memory key or inhibit writing while there is no input video signal, and to display an error warning if the memory key is operated at that time. However, because the operator cannot quickly understand why the memory key is disabled and what kind of error happens, the conventional solution is insufficient.
In addition to these problems, since the number of keys for entering or selecting conditions for printing has increased with the increase of functions available in a single high-tech video printer, the lowered facility in operation and the increased production cost have become new problems.